The transportation system of the present invention is of the general type described in U.S. Pat. Nos. 3,266,848 and 3,586,382, both of which issued in the name of Alan R. Pitkanen. A transportation system is described in each of the patents in which a vehicle is propelled along the top of a duct while supported on a cushion of escaping pressurized air traveling longitudinally along the path of the vehicle. The system described in each of the patents comprises a duct for conducting a flow of pressurized air, and a flexible belt positioned horizontally underneath a grating which is mounted in the top of the duct. The belt serves as a valving means for the passage of pressurized air through the grating so that the vehicle may be supported on a cushion of air and so that it may be propelled by the air along the top of the duct.
As mentioned above, the transportation system of the present invention is of the same general type as that described in the patents. However, the improved system of the present invention is constructed in such a manner that the vehicle is provided with at least one vane which is positioned within the duct and which responds to pressure differentials within the duct to provide a positive force for propelling the vehicle along the top of the duct.
The transportation system of the invention is advantageous in that it is noiseless and inexpensive because it involves vehicles which are positively driven at high rates of speed without friction losses. The system of the invention has a "fail-safe" feature since if for any reason air pressure is lost, the vehicle merely drops to the top surface of the duct and stops.